An arc furnace designed to melt down scrap and process a resulting melt basically comprises a refractory lined vessel having a refractory hearth for containing the melt and a roof having openings through which arcing electrodes are passed. The vessel can be charged with scrap, and the electrodes adjusted to form arcs with the scrap, and during this meltdown phase, the arcs do not operate smoothly, causing the electrodes to receive relatively violent transverse movements, the impact of which is received by the roof.
The vessel has an opening in its side above the hearth, leading to a pouring spout, and is designed to tilt in the direction of the opening so that a melt in the hearth can the poured from the vessel.
The inside of the roof is directly exposed to thermal radiation from the arcs and from the melt in the hearth.
There are various prior art proposals for using water-cooled segments for an arc furnace roof, exemplified as follows: German Offenlegungsschrift No. 26 39 378, German Offenlegungsschrift No. 2 546 142, German Publication "Fachberichte Huttenpraxis Metallverarbeitung", 1978, pages 77-81.
The object of this invention is to provide an arc furnace roof formed from cooled segments which do not require thick refractory linings on their bottoms exposed to the furnace heat, and which is particularly resistant to damage in the area adjacent to the arcing electrodes. It is there that the roof should be particularly capable of absorbing radial impact loads from the transverse movements of the electrodes.